Design and Development of SIS Mixers for ALMA Band 10

• Published in: IEEE transactions on applied superconductivity Vol. 17; no. 2; pp. 363 - 366
• Main Authors: Wenlei Shan, Shengcai Shi, Matsunaga, T., Takizawa, M., Endo, A., Noguchi, T., Uzawa, Y.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01.06.2007; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Aluminum; Applied sciences; Atacama Large Millimeter Array; Circuit properties; Circuit testing; Compound structure devices; Current density; Density; Electric, optical and optoelectronic circuits; Electrical engineering. Electrical power engineering; Electronic circuits; Electronics; Exact sciences and technology; Frequency; High temperature superconductors; Insulators; Land surface temperature; Microstrip; Microstrip lines; Microwave circuits, microwave integrated circuits, microwave transmission lines, submillimeter wave circuits; Mixers; Niobium; Receivers; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Signal convertors; SIS junction; submillimeter wave mixer; Superconducting device noise; Superconducting devices; superconducting microstrip line; Tuning; Various equipment and components; Waveguides; Submillimeter wave mixers; Insulator; SIS structure; High density; Optimization; Wiring; Microstrip line; Superconducting materials; submillimeter wave mixer; Metal coating; Transmission line; SIS junctions; SIS junction; Microwave receiver; Current density; Low temperature; superconducting microstrip line; High strength current; Low noise circuit; Dielectric materials; Experimental study; Waveguide; Tuning; Residual resistivity; High current; Atacama Large Millimeter Array; Noise temperature; Transmission loss
• ISSN: 1051-8223; 1558-2515
• DOI: 10.1109/TASC.2007.898594

We present the design and preliminary experimental results of superconductor-insulator-superconductor (SIS) mixers for Atacama large millimeter array (ALMA) band 10 (780-950GHz) receivers. To achieve wide frequency coverage as well as low noise temperature, we integrated high current density (10 kA/cm 2 ) and small-sized (one micrometer in diameter) Nb/AlO x /Nb SIS junctions with a tuning microstrip line using NbTiN ground plane and Al wiring layers. High quality NbTiN films with Tc reaching 14.5 K and Al films with residual resistivity ratio as large as 15 have been achieved. To minimize the waveguide transmission loss and facilitate the fabrication of mixer block, a full height waveguide was adopted. The waveguide probe was optimized to achieve low input impedance in the frequency range of 780-950 GHz while adopting a backshort cavity of zero depth. Preliminary RF testing with a Nb/Al microstrip tuning circuit demonstrated a DSB receiver noise temperature about 400 K at 832.5 GHz, which promises the accommodation of receiver performance in ALMA specification with low loss NbTiN/Al microstrip lines.